| Chaba (0417) 台风变性前后热力结构特征 |
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| 引用本文： | 钟颖旻,徐明,王元.Chaba (0417) 台风变性前后热力结构特征[J].应用气象学报,2008,19(5):588-594. |
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| 作者姓名： | 钟颖旻 徐明 王元 |
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| 作者单位： | 1.中国气象局上海台风研究所, 中国气象局台风预报技术重点开放实验室, 上海 200030 |
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| 摘 要： | 运用美国NOAA-15极轨气象卫星高分辨率的AMSU探测资料, 结合NCEP/NCAR再分析资料和GMS-5气象卫星红外云顶亮温(TBB)资料, 对2004年Chaba(0417)台风(TC)变性前后的热力结构特征进行分析。发现变性前TC暖核结构呈对称分布, 在高空存在一强暖心; 变性后原TC对称暖心结构消失, 存在于温带气旋上空的相对暖区呈现出倾斜的非对称分布, 在高、低层各形成一弱的暖区中心, 锋面的斜压特性显著。通过热力结构对比, 进一步揭示出TC在向高纬度方向移动时, 与中纬度系统相互作用发生变性, 实质上是两个相继过程, 即热带气旋的消亡和温带气旋的生成发展。TC西侧高空干冷空气的入侵下沉, 破坏了其发展所需的水汽条件, 造成TC对称暖核结构的削弱和损毁。与此同时, 在TC残留区域, 由于空气较暖且存在气旋式环流, 暖空气在东侧呈气旋式上升, 与西侧高空入侵下沉的干冷空气形成偶极, TC暖气团与冷空气相交发展形成斜压的结果, 则为温带气旋的生成和发展创造了有利条件。
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| 关 键 词： | AMSU-A 台风 变性 热力结构 |
| 收稿时间： | 2007-07-23 |
Thermal Structure Characteristics of the Extratropical Transition of Tropical Cyclone Chaba (0417) |
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| Zhong Yingmin,Xu Ming and Wang Yuan.Thermal Structure Characteristics of the Extratropical Transition of Tropical Cyclone Chaba (0417)[J].Quarterly Journal of Applied Meteorology,2008,19(5):588-594. |
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| Authors: | Zhong Yingmin Xu Ming and Wang Yuan |
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| Institution: | 1.Shanghai Typhoon Institute, Laboratory of Typhoon Forecast Technique, CMA, Shanghai 2000302.Key Laboratory of Mesoscale Severe Weather/MOE, Nanjing University, Nanjing 210093 |
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| Abstract: | The thermal structure characteristics of tropical cyclone(TC)Chaba(0417)over the western North Pacific Ocean in 2004 in its extratropical transition(ET)period are analyzed with the temperature data from NOAA-15 AMSU-A, reanalysis data from NCEP and black body temperature(TBB)data from GMS-5. It is found that the original symmetric structure of warm core is destroyed and sinking with slope asymmetric distribution in the ET process, and there is a weak warm center in the upper and lower troposphere respectively in the core region. The remarkable front characteristic in Chaba circulation appears distinctly. Through the thermal structure analysis, it is found that the extratropical cyclone is developing while Chaba is decaying. The decay of the tropical cyclone and the development of the extratropical cyclone occur successively while the tropical cyclone moves to the higher latitude area and interacts with preexisting mid-latitude system. The obstruction of water vapor transport and the symmetric warm core destruction are caused by the intrusion of cold air from middle upper troposphere in west semi-circle of Chaba. At the same time, a dipole is caused and advantaged conditions for extratropical cyclone development is initiated by the weak warm air which ascends cyclonically in the east semi-circle of the tropical cyclone and the cold dry air which descends in the west semi-circle of the tropical cyclone. Consequently, a sort of conceptual model of ET process in the Western North Pacific Ocean is proposed. The development of the extratropical cyclone is the result of the interaction between the warm air ascending in the east semi-circle of the TC and the cold air from mid-latitude in the west semi-circle of the TC.The beginning of the extratropical transition period of tropical cyclone Chaba in the Western North Pacific is defined while the tropical cyclone circulation encounters the preexisting mid-latitude baroclinic front zone and interacts with it. The end of the extratropical transition period of tropcical cyclone Chaba is defined while the original closed circulation of tropical cyclone enters completely into the westerly circulation in 500 hPa and evolves into a baroclinic storm, it indicates that tropical cyclone Chaba is captured by westerly circulation and an asymmetric distribution of clouds in the extratropical cyclone is remarkable. |
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| Keywords: | AMSU-A |
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